I realize that it has been discussed before in this forum, but i still are a little puzzled regarding taking the valve clearances. Since the engine have hydraulic lifters in the first place, how come they can develop ticking noise? The clearance should be taken out by the fancy oilfilled lifter.. right?
-And also, when taking measurement, how can i be sure there is no oil in the lifter to interfere with the clearance?

I have taken the path down the rabbit hole in an effort to get rid of chainslaprattle and other ticking noises, so the whole front of the engine is removed together with chains and tensioners (what and absolute terrible job), so i do have full access to cams etc. There is also going to be new seals to the VVT´s, whatever i can find, i even consider to open and clean the VVT actuators inside. New chain and tensioners of course... funny enough the old chains and tensioners look absolutely fine...

E

 

Are you sure that the 4.2 has hydraulic valve lifters? The 4.0 does not and I thought that the mechanics were basically the same?

The VVT and tensioners both rely on hydraulic pressure so any initial noise could be from those sources.

Richard

 

Another common top end noise is piston slap. My 2002 XKR has it, and it’s very noticeable when the engine is cold. But once it’s fully warmed up, and the thermostat is starting to open, 99% of the noise is gone.

Z

 

No hydraulic lifters, as mentioned.

While you're in the engine, be sure to take off the sump and check for debris in the oil pickup, as that can reduce oil pressure and cause problems. I had VVT rattle that was helped when I cleared bits of orange plastic from the pickup, presumably bits of chain tensioner from before a previous owner upgraded to metal tensioners. Obviously you are less likely to have any blockages as your car always had the better tensioners, etc, but worth a look.

 

Aha! Thanks for info. I somehow assumed that the V8 had hydraulic lifters... what a bummer.. then it makes more sense to make an serious valve clearance check. As mentioned it has metal tensioners since new, but for sure, enough miles on the clock and it makes sense to at least have a looksie.. My car have made about 160 000 Km.
I have been thinking of removing the oil pan too just in case..

I have had a look at an cut through picture of the VVT actuators and there is a big o-ring sealing the "piston" thingie inside.. hm.. and the VVT housings (with the solenoids) has two special made hard seals each..
Btw, the VVT-solenoids, is it confirmed that they actually can cause noise related problems? They route oil to move the pistons in the VVT actuators either way.. i cant really see what would make the noise..

Update; i did some measurements yesterday on the LH bank and i could push through a .30mm feeler on all exhaust valves.. (0.27mm max), also had 3 valves on intake side where i cold push a 0.25mm through (0.22 max).. they came through with a not very hard, but a firm push... i have a little trouble to decide if its good or not.. But it feels that i could add 0.2-0.3mm on the shim thickness..
Thoughts?

/E

 

NO! Not 0,2-0,3 mm, you are talking about 0,02-0,03 mm and that is NOT your problem. If your valve clearance was 0,2 mm to big, it would be ticking, but 0,02 mm will not

 

Hmm... ofcourse, not .3, its .03mm.

Bought a micrometer and a precision feeler gauge... i have to go to the bottom of this.

One discovery though... and a really annoying one; -someone installed cams from a supercharged car on this non-supercharged XK. I realized this when i checked the cam lobe lift. I have 9.0mm and its supposed to be 8.5mm, the exhaust cam has lower lift; 8.1mm instead of 8.5mm.
So, obviously its possible to slap a VVT actuator on a S/C cam.. else it might be hard to make it run properly..

-With higher lift on the intake and lower lift on the exhaust on a non S/C engine, its not by much, but what implications might this have in the long run? It does run like a charm at the moment though..

And now i also have to check partnumber on everything to make sure that i have the correct compression rate... is the connecting rods shorter on the S/C??

/E

 

..With both cams out and checked i could conclude that the cams are not even from a supercharged engine, they must all from an 4.0L engine Cam lobe lift is about 9mm on all cams.
Is this common?, i mean, it must have been a workshop that has mixed the heads up believing they are the same.. or are there any benefits?
Or.. the whole engine is swapped out to an 4.0L, what a bummer that would be..

 

Read the engine number, it's the the only way to know which engine block you have.

 

.. checked cam and cylinder head part numbers and everything points to parts belonging to the right year and and engine type. What i cant get my head around is why cam lobe lift differ from what i measured and what is stated in the engine manuals.
I got the number from LH aft side under the manifold next to a shiny plug "031007 0810" witch i belive is the date the engine was assemblied.

Well, im going to roll with it and keep going. :-)

/E

 

Are you measuring the cam lift with a dial gauge? Any other way will not be accurate enough.

Richard